Closure cap and the like and method of making same



Jan. 9, 1940. w, c. MILLS 2,186,728

CLOSURE CAP AND THE LIKE AND METHOD OF MAKING SAME Filed April 17, 1957 s Sheets-Sheet 1 TNvENTo War/[ace COW/7S (/ITTOPN 5 5 Jan. 9, 1940. w. c. MILLS 7 2,135,723

CLOSURE CAP AND THE LIKE AND METHOD MAKING SAME Filed April 17, 1957 3 Sheets-Sheet 2 iNVENTOL 1 67//0'6'6C.' ///s v ICATTORBEQG Jan. 9, 1940. 2,186,728

CLOSURE CAP AND THE LIKE AND METHOD OF MAKING SAME W. MILLS Filed April 17, 195'? 3 Sheets-Sheet 5 m z i.

Patented Jan. 9, 1940 UNITED STATES PATENT OFFICE Wallace C. Mills, Rockford, Ill., assignor to J. L. Clark Manufacturing Company, Rockford, 111., a

corporation of Illinois Application April 17, 1937, Serial No. 137,540

9 Claims.

The invention pertains to sheet metal closure caps and similar articles, having a top or end wall and a peripheral skirt of substantial depth; and it concerns particularly the production of such articles, having a skirt of double wall construction including an outer wall portion and a wide internal reinforcing hem formed integral with the outer wall portion.

Closure caps and similar articles have heretofore been made with skirts provided with an internal hem, but considerable difliculty is experienced in producing such articles commercially when it is attempted to make the internal hem of substantial depth. The primary object of the present invention is to provide a closure cap or the like, having a wide internal hem, and which may be produced economically on a commercial 'scale..

A further object is to provide a closure cap of the character indicated, in which the wide internal hem is formed with a plurality of internal projections or protuberances forming lugs for engaging the threads of a jar or other container, with such lugs invisible from the exterior of the cap.

Another object is to provide a novel and advantageous method of making closure caps and similar articles of the character above set forth.

Further objects and advantages of the invention will become apparent as the following description proceeds and the features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of the invention, reference may be had to the accompanying drawings, in which 1 Figure 1 is a perspective view of a container provided with a sheet metal closure cap fash- 40 ioned in accordance with the present invention.

Fig. 2 is a side elevation partially in section, of the container shown in Fig. 1, the central portion thereof being broken away.

Fig. 3 is a transverse sectional view along the line 3-3 in Fig. 2.

Figs. 4, 5, 6, 7 and 8 illustrate successive steps in the formation of the cap.

Fig. .9 is a perspective view of the completed cap.

Fig. 10 is a similar view of a somewhat modified form.

Fig. 11 illustrates a suitable mechanism for converting the sheet metal blank shown in Fig. 4 into the form shown in Fig. 5.

plications.

' tainer.

peripheral side wall b. 'The latter is of a depth the shape of the sheet metal blank shown in Fig. 5 to that shown in Fig. 6. I

Fig. 13 shows a mechanism for changing the shape of the sheet metal blank from that shown in Fig. 6 to that shown in Fig. '7.

Fig. 14 shows a mechanism for changing the shape of the sheet metal blank from that shown in Fig. 7 to that shown in Fig. 8.

Fig. 15 shows a mechanism for changing the shape of the sheet metal blank shown in Fig. 8 10 to that shown in Fig. 9. i

Fig. 16 is an enlarged fragmentary sectional View of the side wall of the cap, illustrating particularly the position of the neck portion of the blank before-and after the bending operation is 15 "completed. i

For purposes of illustration, 1 have shown and will hereinafter describe my invention as applied to the manufacture of closure caps for jars or other containers, but it should be understood that the invention is susceptible of various other ap- Referring first to Figs. 1 and 2, l4 designates a cylindrical sheet metal container' having a screw threaded neck portion I5 to which is applied a closure cap generally designated l6 and constructed in accordance with my invention.

The cap l6 comprises an end or top wall I! and a peripheral skirt l8 having an outer wall portion 20 and an inner wall portion 2| in the form of a wide integral hem lying flat against the outer wall portion 20. In order that the latter may thus accommodate the hem, which is of smaller diameter, the hem is contracted by an amount substantialy corresponding to the thickness of the metal. At spaced points the hem 2| is formed with a plurality of inwardly projecting lugs 22 spaced apart and spirally disposed for coaction with the threaded neck l5 of the con- The improved cap is made from a fiat sheet of metal which is first drawn in a well known manner to form a cylindrical cup-shaped shell A (Fig. 4) having a transverse end wall I! and a axially of the shell substantially twice the depth of the skirt to be formed, it being assumed that the internal wall portion or hem is to be made substantially coextensive with the outer wall portion.

In forming the cap from the shell A, the neck portion 2| of the side wall is contracted to a relatively smaller diameter than the base portion b of the shell side wall. This inwardly offially and finally outward to form the inner wall illustrated in Fig. 11. As therein shown, the shell A is positioned within an outer die having a lower section consisting of two members 24 and 24*- coacting to form a recess 25 of fixed diameter and an upper section composed of a plurality of radially movable jaws 26. Cooperating with the said outer die is an inner die composed of a plurality of die blocks 21 having segmental curved peripheral surfaces and movable radially upon a thin disk 28. An inner power actuated plunger 28 has annular tapered surfaces 29 and 29 engageable with complemental sloping inner surfaces of the die blocks 21; and an outer plunger 30 has tapered surfaces 3| and 3| arranged to coact with complemental surfaces 3| and 3| formed on the outer surfaces of the jaws 26 of the upper male die section.

The recess 25 in the outer die is of substantially the same diameter as the external diameter of the shell A, and is of a. depth corresponding to the axial length of the outer Wall portion 20. In the descent of the plungers 28 and 30, the inner die members 21 are forced radially outward so as to press thelower portion of the shell firmly against the inner peripheral wall of the recess 25, and the radially movable jaws 26 constituting the upper section of the outer die are moved inwardly against the upper protruding edge portion or neck 2| of the shell to contract the same to the desired reduced diameter.

While the shell is being operated upon to form the contracted neck 2|, the fastening lugs 22 are also preferably formed although they may be formed at some other point in the process. For this purpose, certain of the inner die members 21 are formed with a plurality of projections 32 coacting with complemental recesses in the outer jaws 26 so as to form indentations 38 in the upper inner surface of the neck 2 I, thereby forming the outwardly projecting lugs 22. In their radial movement the inner die members 21 slide upon the disk 28 which rests upon the bottom of the shell so as to avoid scoring the latter.

After the upper edge portion 2| of the shell A has been offset with respect to the lower wall portion 20, as described, it is bent inwardly by applying bending or folding pressures .thereto at spaced points simultaneously. In the event that indentations such as 38 are formed in the upper edge portion 2| of the shell, the bending pressures are applied at points intermediate these indentations so as not to disturb their contour. The inwardly and downwardly directed bending forces are applied so as to form a series of transverse bends or folds c with a folding and unfolding action until the portions of metal which they contact are bent substantially into face-to-face contact with the adjacent inner surface of the outer wall portion 20 as shown in Fig. 8. The term downwardly directed bending pressure as used herein is simply a convenient mode of expressing the idea of applying a pressure generally axially of the shell in the selected direction of bending. The operation is preferably carried out in several steps in order to simplify the apparatus required for effecting it. In addition, the bending pressures are preferably applied simultaneously at the several spaced points in order that the folding or transverse bending will be carried out smoothly about the continuous side walls of the shell. A convenlent mechanism for effecting this folding operation is shown in Figs. 12 and 13.

It has been found that a critical relation exists between the diameter of the shell and the number of transverse bends or folds c which should be formed therein to attain best results. In general, the number of folds should be such that the metal bends in the form of small triangles d at the roots of the folds and the juncture with the body 20 (Fig. 7). If too many folds are used, these triangles are eliminated and the folds join the shell body 20 at sharp points which produces an uneven edge in the final cap. On the other hand, if too few folds are utilized, the triangles d are so wide that the cap is difficult to form and pronounced markings appear on the inner wall surface. It has been found that the ratio of the number of folds to the diameter of the cap in inches should be approximately five to one. Thus, for a 2% inch diameter cap, best results are had with ten folds, and for a 1 inch diameter cap, eight folds.

After having been operated upon in the mechanism shown in Fig. 11, the shell A is transferred to the mechanism shown in Fig. 12 in which it is positioned in a recess 43 formed in the upper face of a fixed base 44. The recess 43 surrounds the entire lower body portion 20 in order to maintain its cylindrical shape. A power actuated vertically movable plunger 45 is moved toward and into engagement with the open end of the shell. In the continued movement, a plurality of bars 46 fastened within a conical recess 41 in the lower face of the plunger 45 contact the edge portion 2| of the shell at points intermediate the indentations 38, thus bending the same inwardly in sharp V-shaped folds so that the shell assumes the form shown in Fig. 6 to facilitate the subsequent bending operations.

Of primary importance in the operation of bending the neck 2| inwardly to form the internal wall or hem 2| is the preliminary shaping of the shell to form the lower enlarged wall portion 20 and the relatively smaller neck 2|. As shown in Fig. 5, this shaping operation results in the formation of an upwardly facing shoulder 48 extending circumferentially of the shell, and it has been found that this shoulder has the effect of controlling the metal so as to insure that the line of fold or bend will be maintained uniformly throughout the circumference of the shell.

The bending operation initiated in the mechanism shown in Fig. 12 is continued in the mechanism shown in Fig. 13 to which the shell A is next transferred. This mechanism is substantially identical with that shown in Fig. 12 and includes a supporting member 44 having a cylindrical recess 43 in its upper face adapted to receive the shell. A power actuated plunger 45 is provided with a conical recess 47 in its lower face disposed at a more acute angle than the bending bars 46 of the mechanism shown in Fig. 12 so that upon contact with the edge portion 2| of the shell, this edge portion is bent inwardly, thus assuming the form shown in Fig. 7.

The shell A is then transferred to a third plunger type mechanism shown in Fig. 14. In this operation, the edge portion 2| of the shell is bent into the position shown in Fig. 8. When in this position the transverse bends or folds c are in close proximity to the inner surface of the shell body portion 20. In the mechanism shown in Fig. 14, the shell A is positioned on a cylindrical spring pressed supporting plunger 49 slidably mounted within the complemental cylindrical recess 50 in a fixed supporting member 5|. The bending mechanism also includes a vertically movable power actuated plunger 52 carrying a cylindrical die member 53 on its lower end, this die member being surrounded by an annular plunger member 54. In the initial downward movement of the plunger 52 the lower nose portion 55 of the annular plunger 54 engages the shell A and forces the same downwardly into the recess 50. A series of helical compression springs 56 connecting the annular member 54' and plunger 52 permits relative downward movement of'the die member 53 with respect to the annular member 54 after the latter has engaged the upper surface of the base 5|. Thus, in the continued downward movement of the power actuated plunger 52, the die member 53- is moved toward and into engagement with the inwardly folded portion of the shell A and forces'the same downwardly into the position indicated in the left-hand side of Fig. 14. It will be noted that recesses 51 are formed in the side of the die member 53 in order to receive the indentations 22 previously formed in the neck portion 2| of the shell.

After the blank or shell has been fashioned into the shape shown in Fig. 8 by the mechanism of Fig. 14, the edge portion 2W is flattened against Y the adjacent inner surface of the larger diameter lower portion 20, thereby completing the formation of the internal wall or hem 2 I. This fiattening operation may conveniently be performed in a plunger-type bending mechanism shown in Fig. 15. This mechanism includes in general a fixed base member 58 having a cylindrical recess 59 therein adapted to receive the shell A on a spring pressed plunger 60 within the recess. The upper section of the die mechanism includes a plurality of radially movable cooperating die members 6| having curved peripheral faces and carried by a power actuated plunger 62. The die members 6| are mounted on a thin disk-shaped wear plate 63 and are provided with inclined inner cam surfaces 64 cooperating with a complemental inclined nose portion 65 on the plunger 62. A coil spring 66 serves to hold the die members 6| in position on the end of the plunger. Upon downward movement of the plunger 62, the die members 6| are inserted within the shell A until the disk 63 contacts the bottom of the shell. Upon subsequent downward movement of the plunger 62 the coacting cam surfaces 64 and 65 cause the segmental die members 6| to be moved outwardly, thus forcing the portion 2| of the shell into face-to-face engagement with the outer wall portion 20, as shown in Fig. 16. Suitable recesses (not shown) are of course formed in the segmental die members 5| so that the lugs 22 formed by the indentations 38 will not be disturbed during such flattening operation. After the flattening operation performed by the mechanism of Fig. 15, the shell A is in the form shown in Fig. 9 in which the outer surface of the skirt prese'nts. a smooth pleasing contour from which no metal has been displaced for forming the securing lugs. Also, the raw metal edge of the shell is disposed substantially at the junction line between the top wall of the cap and the outer skirt wall, thus protecting the same.

As shown in Fig. 2, the internal hem 2| of the completed cap engages snugly against the inner surface of the outer wall portion 20. This result is made possible by the preliminary shaping of the shell so as to provide an outer wall or base portion of sumcient diameter to accommodate the hem 20 which is of smaller diameter. The shoulder 48 formed in such preliminary shaping operation performs the important function of providing a definite line along which the metal bends in the folding operation even though there is no internal support to define the point of bending. As a result, all points along the folded edge in the finished cap are disposed in a common plane and any tendency to form an uneven edge is overcome effectually. Formation of the drawn blank with the connecting edge portion or shoulder 48 before bending the neck inwardly is also advantageous in that the strain on the metal along the line of fold appears to be relieved sufficiently to avoid tendency of the metal of the hem to spring back away from the outer wall.

In some instances it may be desirable to form projections on the outer surface of the cap skirt both fordecorative purposes and in order to make it easier for the user to grip the'same. To this end, outwardly extending indentations 50* may in the final operation be formed in both the inner and outer cap skirt walls intermediate the lugs 38. These indentations also serve to cover any marring of the surface of the inner cap skirt wall causedby the contact thereon of the bending bars.

It will be observed that by my invention it is possible to produce economically and on, a commercial scale closure caps and the like of a very advantageous character. Of primary importance is the initial shaping of the peripheral side wall of the cup-shaped shell so as to enable the inner wall portion or hem to retain a position snugly against the outer wall portion, thereby forming a thin double wall of great stren'gthand rigidity.

Another feature of importance is the formation of a series of spaced transverse bends on the edge portion of the side wall of the shell with a folding and unfolding action while such edge portion is being bent first into transverse relation to the outer side wall of the skirt and then into parallel relation in face-to-faee contact therewith. Thus, the metal of the edge portion is at all times kept under positive control during the edgewise contraction thereof incident to the operation of bending it into transverse relation to the base portion forming the outer side wall of the skirt. Moreover, as has been previously noted, the relation of the number of folds to the diameter of the shell is also of importance in this folding and bending operation.

Although a particular application of the invention and illustrative embodiment thereof have been described in some detail, there is no intention to thereby'limit the invention to such illustrative application or embodiment but on the other hand, the appended claims are intended to cover all modifications within the spirit and scope of the invention.

I claim as my invention:

1. The method of making sheet metal closure caps and similar articles which comprises forming a cup-shaped shell having an e d wall and a peripheral side wall, shaping sai side wall to form a base portion and a neck portion with the latter offset inwardly from the base portion soas to form an annular shoulder, and simultaneously applying bending pressures at spaced points tothe neck portion to bend the neck portion inwardly about said shoulder in a direction inwardly and axially of the shell so as to form a series of transverse folds, and finally forcing the neck portion outwardly while flattening said folds to remove the same.

2. The method of making sheet metal closure caps from a shell having an end wall and an annular side wall, which comprises, forming at spaced points a plurality of outwardly projecting proturberances in said side wall in the portion thereof adjacent its free edge, bending the side wall inwardly along a line spaced from its free edge while simultaneously forming transverse folds between the location points of said protuberances, and finally bending said free edge portion axially and then outwardly to remove said transverse folds and form an internal hem, smooth except for said protuberances.

3. The method of making closure caps and similar articles from a sheet metal cup having an end wall and a peripheral annulus, which comprises shaping said annulus to form an outer side wall intermediate its ends of greater diameter than the edge portion thereof, bending the edge portion of said annulus inwardly about the peripheral line of juncture between said edge portion and said portion of greater diameter while simultaneously folding the same transversely at a plurality of spaced points, and then bending the inwardly bent edge portion axially and finally outward while unfolding said transverse folds so as to form a wide internal hem.

4. The method of making closure caps and similar articles from a sheet metal cup having an end wall and a peripheral annulus, which comprises shaping said annulus to form an edge portion of smaller diameter than the'base portion thereof adjacent the end wall, and folding the edge portion of the annulus inwardly about the peripheral line of juncture between said edge portion and the base portion and snugly against the inner side of the base portion while supporting the outer surface of such base portion about its entire periphery and width against outward movement.

5. The method of making closure caps, which comprises, forming a cup-shaped shell having a cylindrical annulus, shaping the annulus to form an outer side wall for the cap of greater diameter than the edge portion and a free edge portion having a plurality of outwardly projecting protuberances, bending the free edge portion of said annulus inwardly at a plurality of spaced points to form a plurality of transverse folds between said protuberances and then bending the inwardly bent edge portion axially and finally outward while straightening said transverse folds so as to form an internal hem having inwardly projecting lugs formed by said protuberances.

6. The method of making closure caps or the like which comprises initially forming a cupshaped shell having an end wall and an annular side wall, bending the side wall inwardly along a line spaced from the edge thereof while simultaneously forming a plurality of sharp V-shaped folds therein separated at their roots by small triangular portions of metal, and then forcing the inwardly bent edgeportion axially and finally outward while straightening out the aforesaid folds.

'7. The method of making closure caps or the like which comprises initially forming a cupshaped shell having an end wall and an annular side wall including a base portion adjacent the end wall of greater diameter than the free edge portion and separated therefrom by an annular shoulder, bending the edge portion of the side wall inwardly about the shoulder while simultaneously forming a series of folds therein equal in number to approximately five times the diameter of the shell expressed in inches, and then forcing the inwardly bent edge portion axially and finally outward while straightening out the aforesaid folds.

8. The method of making sheet metal closure caps, which comprises shaping a single piece of sheet metal into the form of a cup having a circular end wall and a cylindrical side wall, then shaping the side wall to provide a cylindrical base portion and a cylindrical neck portion of slightly less diameter than the base portion with an annular shoulder connecting the two portions, and finally bending the preformed neck portion of smaller diameter inwardly'at said shoulder and thence downwardly and finally outwardly into concentric parallel relation to the base portion.

9. A closure cap comprising a single piece of sheet metal of generally cup-shaped configuration presenting an end wall bordered by an integral cylindrical skirt, said skirt comprising an outer cylindrical shell of substantial depth integral with said end wall together with a wide inner hem integral with the outer edge of the shell, said shell and hem being preformed with each in cylindrical shape and with the hem of slightly less diameter than the shell and connected thereto by an annular shoulder, said hem being bent inwardly about said shoulder to fit snugly within said shell, said hem having inwardly propecting integral protuberances thereon engageable with a container to which the closure is applied and said protuberances being hidden from the exterior of the closure by the overlying portion of the outer shell which is free of complr mental identations, said hem lying smooth alln snug against the inner face of the shell exce l at said protuberances.

WALLACE C. MILLS. 

